The long-term objective of the proposed research is to better understand the nature of intellectual development across the adult life span. Rather than concentrating only on process (e.g., working memory, abstract reasoning) or on common cultural knowledge (e.g., vocabulary), this project concerns knowledge structures, that is, what adults know, even though such knowledge may not be universal, or common to a dominant culture. Specifically, this project focuses on delineating the knowledge structures of adults, and demonstrating the relationships between knowledge structures and other critical individual-differences traits, within an integrated framework for adult intellectual development, called PPIK for intelligence-as-Process, Personality, Interests, and intelligence-as-Knowledge. The framework draws on extant measures of intellectual process (and core cultural knowledge), but also draws from other trait domains, including personality, motivation and interests, self-regulatory processes, and self-concept as important determinants of adult intellectual development. The current proposal represents an important expansion of previous research in four areas: (1) Extending the domain knowledge assessment paradigm to an important real-world knowledge domain (specifically, health and wellness knowledge), where evaluation of age, gender and race differences in health and wellness knowledge and their ability, personality, motivation, etc. correlates will be used to help identify at-risk individuals and groups. (2) Identifying age/cohort differences in knowledge, and the trait determinants of knowledge (across 19 different domains, including science/technology, civics, humanities, business, and current-events, and health/wellness knowledge) across a range of 16 to 75 years of age using a cross-sectional paradigm; (3) Examination of the role of ability, personality, interest, and baseline knowledge determinants of individual differences in short-term domain-specific learning; and (4) Examination of ability, personality, interest, and baseline knowledge determinants of individual differences in self-regulated domain-knowledge learning. This research will yield data that are relevant to a reexamination of the nature of adult intellect -- in a way that will provide a better metric to understanding the intellectual capabilities and limitations of adults at various chronological ages. The research will also help identify the predictors of individual differences in knowledge across a variety of different domains, but especially in the area of health and wellness, by focusing on trait complexes (groups of correlated traits) that support or impede acquisition of knowledge within and between domains.